The Prime Minister told Total Politics magazine that the coalition was the best way to get things done but "if that wasn't the case then we'd have to face the new circumstances in whatever way we should."
The Deputy Prime Minister will say: "He echoed exactly what both of us have always believed: this coalition has been remarkably radical; it still has work to do; and the best way for us to serve and improve Britain is by finishing what we started.
"I am absolutely committed to this coalition lasting until 2015 - as is the Prime Minister."
Claims that it was in either or both parties' interests to "prematurely pull the plug" were wrong, he will suggest.
More top news
Former Oasis star Liam Gallagher has announced that his latest band 'Beady Eye' has split up but did not say why they are calling it a day.
Mike Tindall has agreed a settlement with Express Newspapers over a story about his marriage to Zara Phillips.
The Met Office is warning of persistent heavy rainfall in western Scotland possibly leading to localised flooding.